GB 712 - 2011 is an important standard on structural steel for ships and offshore engineering in China, and the following is an introduction to its main aspects:
1. Scope of application
The standard applies to the manufacture of hull structures, ocean engineering structures and other structures with a thickness of not more than 150mm steel plate, steel strip and steel sections and other steel products. Clearly defined in the field of ships and ocean engineering application boundaries.
2. classification and grade
The standard has a detailed classification of steel, including general strength structural steel and high strength structural steel. And specifies the corresponding Grade Expression, such as general strength structural steel grade to yield strength value to express, high-strength structural steel grade is a comprehensive consideration of the yield strength and quality level and other factors. This helps users to accurately identify and select the appropriate steel.
3. the chemical composition
The chemical composition of steel puts forward strict requirements. Including carbon (C), silicon (Si), manganese (Mn) and other major elements, as well as sulfur (S), phosphorus (P) and other harmful elements of the content limits. Reasonable chemical composition ensures that the steel has good mechanical properties and welding performance.
4. mechanical properties
Yield strength and tensile strength
Provides for different grades of steel in different states of the yield strength and tensile strength of the minimum value to ensure that the steel can withstand the corresponding load in the process of use.
Elongation
The elongation of steel also has a clear requirement, which is related to the plasticity and toughness of steel, to ensure that the deformation of the force will not occur when the brittle fracture.
5.Delivery state
Steel can be provided in a variety of delivery states such as hot rolled, control rolled, normalized, normalized rolled. Different delivery states will affect the mechanical properties and organizational structure of steel, manufacturers need to be based on user needs and standard requirements for a reasonable choice.
6. the surface quality
The standard specifies the surface quality of steel, the steel surface shall not have cracks, bubbles, scars and other defects to ensure the reliability and safety of steel in the process of use.
